It has, for years, been the desire of most technicians to provide a battery back-up system for computers and other sensitive technology which lose memory or other features when the power source is interrupted. In an effort to respond to this need, sophisticated, complex systems have been developed which include separate AC power sources, separate DC battery power sources and a battery charging circuit supplementing the battery source. In addition, complex systems have been needed to sense current loss in the AC system, signal such current loss and switch in the battery power circuit.
The prior art has its disadvantages in that multiple systems required consume an undesirable amount of space, the separate circuitry is undesirably expensive and there always exist the risk of current loss or power droppage during the switch over from the AC source to the DC battery source.